1. Field of the Invention
The present invention relates to an exercise device, and more particularly to an exercise device which includes a mat constructed to achieve its rotation through a certain angle and to stably and tightly hold the ankle portions of a user in a wider contact area, thereby allowing the user to perform a simple exercise, such as a repeated retraction of the upper body of the user, as in sit-ups, under the condition in which the mat is maintained at a horizontal position or a position inclined by an optional angle from the horizontal position.
2. Background Art
Generally, a person, such as a student or office worker, who studies or works in one position for a long period suffers back pain which is the central part of his body, or may be subjected to a variety of diseases through lack of exercise. In order to prevent diseases caused by lack of exercise, exercise devices, which are capable of allowing the user to perform a repeated retraction of his upper body thereby achieving an abdominal exercise or waist exercise, have been proposed to be placed at homes or in health rooms.
However, such conventional exercise devices are expensive due to their need for a complex drive unit for rotating a mat through a desired angle, thereby resulting in an increase in the manufacturing costs. Furthermore, such conventional exercise devices have difficulties in transportation and installation because of an increase in the volume and weight of the entire construction.
Although such conventional exercise devices have a foot holder adapted to hold the feet or ankle portions of a user, it is difficult for such a foot holder to meet different physiques of users because the foot holder is fixed to the mat. Moreover,such a foot holder, which is in contact with the body of the user during an exercise, has the shape of a straight extension. Due to such a shape, the foot holder is in contact with the body of the user in a local fashion. For this reason, the portion of the user's body locally contacting the foot holder is severely pressed. In severe cases, the user may suffer pain. Thus, the conventional foot holder has a problem in that it cannot hold the ankle portions of the user comfortably and stably.